[Slow speed writing to cache. (SOLVED)]

On 8/24/2020 at 2:28 AM, j44rs4 said:

Thx for your reply.

 

Unfortunately I've already activated Direct IO, with no better outcome.

 

I've tried serveral different disks (from nvme, SAS, SSD and SATA) as cache disk, but with the same performance.

 

Is seems like it's not using the cache drive correctly when writing to shared folder. Since I get better speed when writing directly to cache, than writing to shared folder through cache. 

 

1.PNG - Shows copy directly to cache

2.PNG - Shows copy to sharefolder

3.PNG -  Shows copy directly to disk1

 

We’re you able to find a work around or fix for this....

[SSD Cache slow connected to SAS Card]

I need a little help with this I thought I had it solved but I was very wrong, this is the problem I’m having, I have 6 ssd’s connected to a SAS Lsi 2008- 8i card, when write to a cache enable write speed is about 300mb/s but if I share the cache and write to it speeds are about 900mb/s

I can’t figure it out any help would be appreciated 

[Unraid 6.8 Cache Slow]

31 minutes ago, testdasi said:

That's normal shfs overhead. The shares will never reach above about 400-500MB/s. The only way to bypass it is to either use disk share or create custom SMB config to target /mnt/cache/[share] directly.

Thank you I believe I’ve found the problem, this problem didn’t begin until a hardware change I guess unraid with a cache pool on a sas controller, is a no go, the new board I have only have sata to but I connected to that speeds are 500/750 I can’t live with that.....

[Unraid 6.8 Cache Slow]

7 minutes ago, testdasi said:

You might want to write longer description of what you are seeing, with punctuation please.

What do you mean by "I shared the caches speeds are 400/989" and "cache  speeds are 400/400" and "write to the cache directly speeds are go"? What speed is "go"?

 

Also what RAID mode are the 5 SSD's?

Sorry, my sdd pool is in a raid 0, I shared the cache pool and  written to it directly and got speeds of 400/989 but when I write to a share with cache enbabled 400/400 speeds I hope this make sense thank you

[Unraid 6.8 Cache Slow]

1 minute ago, testdasi said:

You might want to write longer description of what you are seeing, with punctuation please.

What do you mean by "I shared the caches speeds are 400/989" and "cache  speeds are 400/400" and "write to the cache directly speeds are go"? What speed is "go"?

 

Also what RAID mode are the 5 SSD's?

Sorry, my sdd pool is in a raid 0, I shared the cache pool and  written to it directly and got speeds of 400/989 but when I write to a share with cache enbabled 400/400 speeds I hope this make sense thank you

[Unraid 6.8 Cache Slow]

1 hour ago, falconexe said:

Yes, I ran into this too, but I solved it with a workaround. Please see here. Good luck!

 

 

thanks for the reply but it didnt work for me

[Unraid 6.8 Cache Slow]

1 hour ago, itimpi said:

I expect you are hitting limitations imposed by the extra overhead of going through the User Share access level code.

how can i fix this

[Unraid 6.8 Cache Slow]

I can not figure out what’s wrong, I will try to explain. I created a share that’s cached, I have 5 Ssd’s in that cache  speeds are 400/400 but it should be faster, I shared the caches speeds are 400/989 I don’t understand this when I write to the cache directly speeds are go but when I write to a cached share speeds cut in half